Suturing instruments are typically used to draw together two or more portions of a subject patient (e.g., tissue such as muscle or skin) or to attach an object to the patient (e.g., to attach a piece of surgical mesh to the abdominal wall of the patient during hernia repair surgery).
Certain suturing instruments employ a needle that precedes a length of suture material through a subject.
For example, U.S. Pat. Nos. 3,470,875; 4,027,608; 4,747,358; 5,308,353; 5,674,230; 5,690,653; 5,759,188; and 5,766,186 generally disclose suturing instruments in which a needle, with trailing suture material, is passed through a subject.
U.S. Pat. Nos. 4,890,615; 4,935,027; 5,417,700; and 5,728,112 generally disclose suturing instruments in which suture material is passed through the end of a hollow needle after that needle has been passed through a subject.
With all of the foregoing devices, a needle must be passed through the subject in order to deploy the suture. This has the disadvantage that the needle typically leaves a larger hole in the subject than is necessary to accommodate only the suture material itself. In this respect it should be appreciated that it is generally desirable to alter each portion of the material being sutured (e.g., tissue) as little as possible during the suturing process.
A suturing instrument has been devised which permits the suture material itself to pierce the subject without the use of a needle. However, this device does not permit adequate flexibility with regard to the amount of tension that may be applied to the suture and tissue.
More particularly, U.S. Pat. No. 5,499,990 discloses a suturing instrument in which a 0.25 mm stainless steel suturing wire is advanced to the distal end of a suturing instrument, whereupon the distal end of the suturing wire is caused to travel in a spiral direction so as to create stitches joining together two portions of a subject. After the spiral is formed, the beginning and end portions of the suture may be bent toward the tissue in order to inhibit retraction of the suture wire into the tissue upon removal of the suturing instrument. The stainless steel wire is sufficiently firm to hold this locking set. In addition, after the spiral is formed, the radius of the deployed suture spiral may then be decreased by advancing an outer tube over a portion of the distal end of the instrument. Again, the stainless steel wire is sufficiently firm to hold this reducing set.
Unfortunately, however, such a system does not permit much flexibility when it comes to the amount of tension to be applied to the subject, since the wire is relatively firm (i.e., firm enough to hold its sets). Such a system also does not provide any flexibility with respect to the type of suture stitch to be applied, since the device is specifically configured to provide only a spiral suture stitch.
In contrast to the aforementioned limitations of the suturing instrument of U.S. Pat. No. 5,499,990, it is desirable that a suturing instrument approximate the portions of the material which is to be joined in the correct physiological relationship, and to urge the portions together with an appropriate amount of force. If too much force (or tension) is applied to the suture material, then the subject portions may become necrotic and/or the sutures may cut through the subject. If too little tension is applied to the suture material, then the healing process may be impaired.
U.S. Pat. No. 4,453,661 discloses a surgical instrument for applying staples. The staples are formed from the distal end of a length of wire. More particularly, the distal end of the wire is passed through a subject and thereafter contacts a die that causes the wire to bend, thereby forming the staple. The wire is sufficiently firm to take on the set imposed by the die. The staple portion is then cut away from the remainder of the wire by a knife. Again, such a system suffers from the fact that it does not permit much flexibility when it comes to the amount of tension to be applied to the subject, since the attachment is effected by a staple which has a pre-defined geometry and is formed with relatively firm wire. In addition, the system is limited as to the type of fastening which may be effected, since the surgical instrument is limited to only applying wire staples.
There is a need, therefore, for a new suturing device that permits minimally disruptive suturing and permits flexibility in the placement, application, and tensioning of the suture material.